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you will see the bike look like this, and you can see each steps of buidling process on the bottom of the screen You can also change the bike according to your needs. For example, if you wanna make a new hole on the bike body, you can click create sketch on the top left corner.
then choose the surface that you wanna modify, as shown,choose the bike body surface
then, you can build sketch on this surfarce, you can choose the shape under "sktech", here I will choose circle you can use the shortcut "D" to change the dimension, after modifying, click "Finish Sketch" on the right side of the screen.
after finishing, you can revise the "skecth" and "extrude" on the bottom of the screen, as shown below.